Switching-key.



E. G. EIDAM.

SWITCHING KEY. APPLICATION FILED JUNE 13, 1910.

1 ,O43,307. Patented Nov. 5, 1912.

111755525 IIJVEHTEF M. 6M EL/WBFD' 5. Elli/EH1 fid UNITED STATES PATENTOFFICE.

EDWARD G. EIDAM, OF ROCHESTER, NEW YORK, ASSIGNOR TO STROMBERG-CARLSONTELEPHONE MANUFACTURING COMPANY, OF ROCHESTER, NEW YORK, ACORPORA- TIONOF NEW YORK.

SWITCHING-KEY.

To all whom it may concern:

Be it known that I, EDWARD G. EIDAM, a citizen of the United States,residing in Rochester, county of Monroe, and State of New York, haveinvented certain new and useful Improvements in Switching-Keys, of whichthe following is a specification.

My invention relates to listening and ringing keys for telephoneswitchboards.

The object of the invention is to improve the construction of switchingkeys of this character to make the parts readily accessible andremovable.

My invention particularly relates to the construction of the'frame uponwhich the switch springs of the key are mounted, which constructionprovides for inexpensive manufacture, rigidity of construction and easein assembling.

My invention is illustrated in the accompanying drawing in -which Figure1 is a side elevation and Fig. 2 is a partially disassembled isometricdrawing.

The frame of my switching key depends from the plate 1 and comprises theside plates 2 and 3, these being stamped from sheet metal and beingexactly alike and preferably screwed to the top plate. These side platesare provided with parallel end plates 4:, 5, 6 and 7 upon which the setsof switch springs 8 are mounted. The end plate 6 lies adjacent the innerface of the plate 4 and is provided with a projecting ear 9, adapted toextend through the opening 10 when the plates 2 and 3 are fittedtogether. Likewise the end plate 5 lies adjacent the inner face of theplate 7 and is provided with the car 11, adapted to fit into an opening,not shown in the drawing, in plate 3, when the plates are fittedtogether. The ear 12 in plate 2 is sheared from the metal from which theplate is formed and is adapted to fit into the notch 13 in plate 7,there being similar ears and notches upon the concealed parts of theplates 3 and 2 so that when the parts are put together they areinterlocked in a manner which prevents the lengthwise movement of oneplate upon the other. .The cars may then be riveted which completes theframe, leaving the lower portion boxlike. The opposite ends of the boxare of double thickness and are drilled and tapped as shown at 15 toprovide means for securing the springs-8 to the frame. The hard rubberplates 14 are inserted between the Specification of Letters Patent.

Application filed June 13, 1910.

Patented Nov. 5, 1912 Serial No. 566,504.

springs 8 and the. plates 4 and 7 for insulatmg purposes.

The upper and inner portions of the plates 2 and 3 are turned downwardlyto form guides for the spring actuating cam 16, which operates about thepivot pin 17 passing through alined holes in the plates 2 and 3. Thespring actuating cam 'is provided with insulating rollers 18 held inplace by pins 19, these rollers being adapted to press outwardly uponthe upper ends of the long springs to deflect theln when the cam istilted. The insulating handle 20 is secured to the screw extendingupwardly from the cam to provide means for tilting the cam. The sets ofsprings used for the listening switch are preferably bent outwardly in amanner well known in the art to provide means for retaining the cam inactuated position when desired while the fingers are removed. Anescutcheon plate 21 shown in Fig. 1 is preferably attached to provide afinished appearance to the upper surface.

Vhile my improvement is described some what in detail, it is to beunderstood that many changes may be made therefrom without departingfrom the spirit or scope of my invention.

What I claim is 1. In an operators key, a frame comprising side plateshaving downwardly and inwardly turned ears and an operating camsupported between and guided by said ears.

2. In an operators key, a frame formed of two similar punchings securedtogether and forming a tubular lower portion,'switcli springs secured onthe opposite sides of said tubular portion and means between the upperends of said springs for operating the springs.

3. In an operators key, a frame formed of two metal punchings, the lowerportion of each of said punc'hings being formed intoparallel plates,spaced from one another and having their edges connected by a thirdplates, two portions of said frame being adapt-ed to fit together sothat surfaces of an outside and an inside face of one part are adjacentan inside and an outside face, respectively, of the other part.

4. In a switching key, a metal frame formed of two parts adapted to fittogether so that surfaces of an outside and an inside face of one partare adjacent an inside and plate in a plane at right angles to thefirstan outside face respectively of the other part and ears formed ofthe metal for securing the parts together.

5. In a switching key, a frame formed of punchi'ngs, a horizontalcross-section of the lower portion of said punchings being substantiallyU shaped, said punchings being adapted to fit together with the outsideface of a limb of one adjacent the inside face of a.

limb of the other, and the inside face of the other limb of the firstadjacent the outside face of the other limb of the second.

6. In a switching key, the combination with a frame formed of twosimilar punch- Copies of this patent may be obtained for five centseach, by addressing the Commissioner of Patents, Washington, D. G.

